#include "bits/stdc++.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 5e5 + 5;
int n, s[maxn], k;
vector<int> g[maxn];
vector<int> grp[maxn];
int lab[maxn], par[maxn], h[maxn];
int deg[maxn];
int find(int u) {
return lab[u] < 0 ? u : lab[u] = find(lab[u]);
}
void join(int u, int v) {
u = find(u), v = find(v);
if (u == v) return;
if (lab[u] > lab[v]) swap(u, v);
lab[u] += lab[v];
lab[v] = u;
}
void pre_dfs(int u, int prev) {
for (auto v:g[u]) {
if (v == prev) continue;
par[v] = u;
h[v] = h[u] + 1;
pre_dfs(v, u);
}
}
void solve() {
cin >> n >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
for (int i = 1; i <= n; ++i) {
cin >> s[i];
grp[s[i]].push_back(i);
lab[i] = -1;
}
pre_dfs(1, 0);
for (int i = 1; i <= k; ++i) {
if (grp[i].empty()) continue;
for (int j = 1; j < (int)grp[i].size(); ++j) {
int u = grp[i][j], v = grp[i][j - 1];
u = find(u), v = find(v);
while (u != v) {
if (h[u] > h[v]) swap(u, v);
join(u, v);
v = find(par[v]);
}
}
}
for (int i = 1; i <= n; ++i) {
if (lab[i] < 0) {
for (auto v:g[i]) {
v = find(v);
if (i != v) {
++deg[i];
}
}
}
}
int cnt = 0;
for (int i = 1; i <= n; ++i) {
cnt += (deg[i] == 1);
}
cout << (cnt + 1) / 2;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
